Chronic Mechanical Circulatory Support for Inotrope-Dependent Heart Failure Patients Who Are Not Transplant Candidates

Current status of mechanical circulatory support: a systematic review

Heart failure is a major public health problem and its management requires a significant amount of health care resources. Even with administration of the best available medical treatment, the mortality associated with the disease remains high. As therapeutical strategies for heart failure have been refined, the number of patients suffering from the disease has expanded dramatically. Although heart transplantation still represents the gold standard therapeutical approach, the implantation of mechanical circulatory support devices (MCSDs) evolved to a well-established management for this disease. The limited applicability of heart transplantation caused by a shortage of donor organs and the concurrent expand of the patient population with end-stage heart failure led to a considerable utilization of MCSDs. This paper outlines the current status of mechanical circulatory support.

Pulsed or continuous flow in long-term assist devices: a debated topic

The end-stage cardiomyopathy is an increasing worldwide problem. Cardiac transplantation lacks sufficient donors to treat all patients, and there is thus debate about alternative strategies. The use of left ventricular assist devices for long-term support is increasing with a positive impact on patient survival. Although there is an ongoing debate regarding the risks and benefits of maintaining pulsatile flow during long-term ventricular assist device support, there has been a significant move towards implantation of continuous flow devices due to the lower surgical morbidity and better long-term reliability of these pumps. The following is a review of the literature on continuous and pulsatile flow for long-term support. Starting from the definition of flow, we analyze the current evidence and consider gastrointestinal complications.

Heart failure in women

Heart failure (HF) has steadily increased in prevalence and affects both males and females equally. Despite this, there has been a significant underrepresentation of women in large scale HF trials. This disparity has lead to a deficit in understanding important gender-based differences in pathophysiology, diagnosis and treatment strategies. We review these gaps and explore a biological basis for varying outcomes. Endogenous estrogen plays an important role in epidemiology and outcome. The administration of exogenous estrogen has had varied success in treatment and is outlined extensively below. Additionally, we highlight unique HF syndromes through pregnancy and important sex-specific issues concerning transplant and mechanical circulatory support. A central theme remains: there is a clear need for increased female recruitment in clinical trials, and more studies exploring the role of gender-based biology in HF treatment.

Current technology: devices available for destination therapy

Left ventricular assist device therapy as a destination therapy for end-stage heart failure has made a large leap with continuous flow devices. Continuous flow does not seem to have a detrimental effect on end-organ function, at least in the midterm. Various expected and unexpected complications have been reported associated with this technology. More experience and research are warranted.

Mechanisms of bleeding and approach to patients with axial-flow left ventricular assist devices

Axial-flow LVADs have become an integral tool in the management of end-stage heart failure. Consequently, nonsurgical bleeding has emerged as a major source of morbidity and mortality in this fragile population. The mechanisms responsible for these adverse events include acquired von Willebrand disease, GI tract angiodysplasia formation, impaired platelet aggregation, and overuse of anticoagulation therapy. Because of ongoing concerns for pump thrombosis and thromboembolic events, the thrombotic/bleeding paradigm has led to a difficult clinical dilemma for those managing patients treated with axial flow LVADs. As the field progresses, advances in the understanding of the pathological mechanisms underlying bleeding/thrombosis risk, careful risk stratification, and potential use of novel anticoagulants will all play a role in the management of the LVAD patient.

Development of magnetic bearing system for a new third-generation blood pump

A magnetic bearing system is a crucial component in a third-generation blood pump, particularly when we consider aspects such as system durability and blood compatibility. Many factors such as efficiency, occupying volume, hemodynamic stability in the flow path, mechanical stability, and stiffness need to be considered for the use of a magnetic bearing system in a third-generation blood pump, and a number of studies have been conducted to develop novel magnetic bearing design for better handling of these factors. In this study, we developed and evaluated a new magnetic bearing system having a motor for a new third-generation blood pump. This magnetic bearing system consists of a magnetic levitation compartment and a brushless direct current (BLDC) motor compartment. The active-control degree of freedom is one; this control is used for controlling the levitation in the axial direction. The levitation in the radial direction has a passive magnetic levitation structure. In order to improve the system efficiency, we separated the magnetic circuit for axial levitation by using a magnetic circuit for motor drive. Each magnetic circuit in the bearing system was designed to have a minimum gap by placing mechanical parts, such as the impeller blades, outside the circuit. A custom-designed noncontact gap sensor was used for minimizing the system volume. We fabricated an experimental prototype of the proposed magnetic bearing system and evaluated its performance by a control system using the Matlab xPC Target system. The noncontact gap sensor was an eddy current gap sensor with an outer diameter of 2.38 mm, thickness of 0.88 mm, and resolution of 5 µm. The BLDC motor compartment was designed to have an outer diameter of 20 mm, length of 28.75 mm, and power of 4.5 W. It exhibited a torque of 8.6 mNm at 5000 rpm. The entire bearing system, including the motor and the sensor, had an outer diameter of 22 mm and a length of 97 mm. The prototype exhibited sufficient levitation performance in the stop state and the rotation state with a gap of 0.2 mm between the rotor and the stator. The system had a steady position error of 0.01 µm in the stop state and a position error of 0.02 µm at a rotational speed of 5000 rpm; the current consumption rates were 0.15 A and 0.17 A in the stop state and the rotation state, respectively. In summary, we developed and evaluated a unique magnetic bearing system with an integrated motor. We believe that our design will be an important basis for the further development of the design of an entire third-generation blood pump system.

Durable mechanical circulatory support devices

Individuals afflicted with advanced systolic heart failure who have become unresponsive to standard medical and electrical therapies are categorized as having American Heart Association stage D heart failure. The high mortality rates for medically treated stage D heart failure have not improved in the last 10 years, and patients at this advanced stage require either palliative measures or surgical management of heart failure. In recent years, surgically implanted ventricular assist devices (VADs) have become available for long-term use and are now commonly used as a therapy for advanced heart failure. The data generated from this early experience have clearly shown that VADs improve survival and quality of life in patients with advanced heart failure when implanted as a temporary measure or as long-term support. However, with a growing heart failure population, there is much work to be done to continually improve VAD technology, patient selection criteria, and postimplantation management to define the optimal role for assist devices in the management of systolic heart failure.

Surgical approach to end-stage heart failure

PURPOSE OF REVIEW

End-stage heart failure is a challenging disease with growing incidence. With decreasing heart transplant rates worldwide organ preserving therapies become, again, of interest. The purpose of the present review is to examine the potential challenges of surgical therapies in patients with end-stage heart failure.

RECENT FINDINGS

The gold-standard for end-stage heart failure is and will be cardiac transplantation. However, due to organ shortage this therapy is limited to a few patients. Therefore implantation of ventricular assist devices (VADs) or long-term minimal-invasive partial support devices will increase. Improvements in device design with smaller devices, easier implantation techniques, and modified anticoagulation outcome and long-term success will likely improve. In addition, good quality of life as destination therapy is almost available. Organ conservation surgery (coronary artery bypass grafting and surgical ventricular restoration or surgical repair of mitral valve regurgitation) in end-stage heart failure patients could not prove the expected results. Transcatheter or minimal-invasive approaches of these therapies might become routine in the near future.

SUMMARY

Due to the overwhelming outcome rates, cardiac transplantation is the most established surgical therapy for end-stage heart failure. VAD therapy is increasing and minimized VADs might further open the market for destination therapy/permanent support.

Mechanical circulatory support as a bridge to transplant or for destination therapy

Mechanical circulatory support (MCS) frequently is used to treat medically refractory end-stage heart failure. Initially designed to be a bridge to transplantation, MCS also has proven itself as a durable therapy for patients who are not transplant candidates. As outcomes for patients with MCS have improved, research interest in device development has flourished, with many new device types under investigation. In addition to improvement of MCS devices, investigational work continues to achieve appropriate patient selection and complication management.

HeartMate® II continuous-flow left ventricular assist system

Left ventricular assist devices (LVADs) have emerged as a beneficial therapeutic strategy proven to improve the morbidity and mortality of patients with advanced heart failure. Continuous-flow rotary LVADs have been developed in the hopes of delivering circulatory support in a more durable manner with fewer device-related complications. The HeartMate(®) II continuous-flow left ventricular assist system (LVAS; Thoratec Corporation, Pleasanton, CA, USA) has become the standard of care for heart failure patients who require long-term mechanical circulatory support. The efficacy of the HeartMate II has been demonstrated in patients where temporary support with an LVAD is needed until a suitable donor organ can be found for transplant (termed 'bridge to transplantation'), as well as for terminally-ill heart failure patients who are not candidates for transplant ('destination therapy'). When directly compared with a pulsatile LVAD, the implantation of a HeartMate II LVAS resulted in an overall improvement in survival with a reduction in the number of device-related complications and adverse events. The purpose of this article is threefold: to describe the history of the development of continuous-flow LVADs; to describe the technology of the HeartMate II; and, finally, to review the clinical outcomes in patients who have been implanted with the device.

Transapical miniaturized ventricular assist device: design and initial testing

BACKGROUND

Left ventricular assist devices are increasingly used to treat patients with advanced and otherwise refractory heart failure as bridge to transplant or destination therapy. We evaluated a new miniaturized left ventricular assist device that requires minimal surgery for implantation, potentially allowing implantation in earlier stage heart failure.

METHODS

HeartWare (Miami Lakes, Fla) developed transapical miniaturized ventricular assist device. Acute (n = 4), 1-week (n = 2), and 30-day (n = 4) bovine model experiments evaluated hemodynamic efficacy and biocompatibility of the device, which was implanted through small left thoracotomy with single insertion at apex of left ventricle without cardiopulmonary bypass. The device outflow cannula was positioned across the aortic valve. The international normalized ratio was maintained between 2.0 and 2.5 with warfarin. Hemodynamic, echocardiographic, fluoroscopic, hematologic, and blood chemistry measurements were evaluated.

RESULTS

The device was successfully implanted through the left ventricular apex in all 10 animals. The device was operated at 15,000 ± 1000 rpm (power consumption, 3.5-6.0 W). The device maintained normal end-organ perfusion with no significant hemolysis (0-30 mg/dL). There were no pump failures or device-related complications. At autopsy, no abnormalities were seen in endocardium, aortic valve leaflets, or aortic root. There was no evidence of thromboembolism or abnormalities in any peripheral end organs.

CONCLUSIONS

We successfully demonstrated feasibility of a novel intraventricular assist device that can be completely implanted through left ventricular apex. This transapical surgical approach eliminates needs for sternotomy, device pocket, cardiopulmonary bypass, ventricular coring, and construction of an outflow graft anastomosis.

Comparison of outcomes in women versus men using a continuous-flow left ventricular assist device as a bridge to transplantation

BACKGROUND

The use of large, pulsatile left ventricular assist devices (LVADs) has been limited in women because of their small body size.

METHODS

We compared the survival outcomes, quality of life, and adverse events in 465 patients (104 women, 361 men) with advanced systolic heart failure in their first 18 months of support with the HeartMate II (Thoratec Corp, Pleasanton, CA) continuous-flow LVAD for bridge to transplantation.

RESULTS

During the first 18 months, there were no differences in survival between women and men while on LVAD support (73% ± 3% vs 73% ± 5%, p = 0.855) but fewer women (40%) underwent heart transplantation than did men (55%; p = 0.001). More women continued on support after 18 months (p = 0.007). Median duration of support was 238 days for women and 184 days for men (p = 0.003). Mortality was 20% for women and 19% for men (p = 0.89). Adverse events were similar, with the exception of hemorrhagic stroke, which occurred more frequently in women (0.10 vs 0.04 events/patient-year, p = 0.02), and device-related infections, which occurred less frequently in women (0.23 vs 0.44, p = 0.006). Functional capacity and quality of life at 6 months improved significantly in women and men.

CONCLUSIONS

Continuous-flow left ventricular assistance as a bridge to transplantation is associated with similar survival rates in women and men. Differences observed in higher stroke rates and fewer infections among women require further study.

Cell therapy for heart failure: the need for a new therapeutic strategy

Improvements in the treatment of ischemic heart disease have led to a significant growth in the numbers of patients with systolic heart failure secondary to myocardial injury. Current therapies fail to address the loss of contractile tissue due to myocardial injury. Cell therapy is singular in its promise of primarily treating this underlying issue through salvage of viable myocardium or generation of new contractile tissue. Multiple cell types have been used to target acute myocardial infarction, chronic ischemic heart disease and heart failure due to infarction. Bone marrow mononuclear cells have been used to increase myocardial salvage after acute infarction. Randomized trials of over 800 patients have demonstrated no safety issues, and meta-analyses have suggested an improvement in left ventricular function in treated patients with trends toward improvements in hard cardiac end points. Cell therapy for chronic ischemic heart disease with bone marrow angiogenic progenitors has shown similar safety and trends toward improvement in function. While these therapies have targeted patients with viable myocardium, myoblasts have been used to treat patients with left ventricular dysfunction secondary to transmural infarction. Cell types with cardiomyogenic potential, including induced pluripotent stem cells and cardiac progenitor cells, offer the promise of true myocardial regeneration. Future studies with these cells may open the door for true myocardial regeneration.

Infectious complications in patients with left ventricular assist device: etiology and outcomes in the continuous-flow era

BACKGROUND

Continuous-flow left ventricular assist devices (LVAD) are increasingly being used in patients with end-stage heart failure and have largely replaced older generation pulsatile devices. While significant rates of infection have been reported in patients with pulsatile device support, incidence and outcomes of this complication for the continuous-flow device patients remain unknown.

METHODS

Between June 2005 and August 2009, 81 patients were implanted with continuous-flow LVADs at Washington University School of Medicine either as bridge to transplantation or as destination therapy. Outcomes of this study included incidence of postimplantation infection, types of infection, microbiologic profile, and association of postimplantation infections with clinical endpoints.

RESULTS

Forty-two patients (51.9%) had at least one type of infection on continuous-flow LVAD support with a mean follow-up period of 9.2 ± 9.2 months. Patients who had an infection on LVAD support had a significantly prolonged hospital stay (37.9 ± 32.0 versus 20.7 ± 23.0 days, p = 0.008) and a trend toward increased mortality (33.1% versus 18.7% at 2 years, respectively, log rank p = 0.102) compared with patients who did not. Subgroup analysis revealed that postimplantation sepsis was significantly associated with increased mortality in the continuous-flow LVAD cohort (61.9% versus 18.0% at 2 years, respectively, in septic and nonseptic patients, log rank p = 0.001). The majority of the sepsis cases occurred before hospital discharge, whereas most of the device related infections occurred after discharge. Resistant Staphylococcus and Pseudomonas species were the most common pathogens leading to device- and nondevice-related local infections. Development of driveline or pocket infection had no effect on survival in patients with continuous-flow assist device support (p = 0.193).

CONCLUSIONS

Even though better clinical outcomes have been achieved with the newer generation continuous-flow devices, infection complications-in particular sepsis-are still a major risk for patients with continuous-flow LVAD implantation. Prevention strategies with aggressive medical and surgical management of infections may increase survival and decrease morbidity among continuous-flow LVAD patients.

Clinical review: mechanical circulatory support for cardiogenic shock complicating acute myocardial infarction

Acute myocardial infarction is one of the 10 leading reasons for admission to adult critical care units. In-hospital mortality for this condition has remained static in recent years, and this is related primarily to the development of cardiogenic shock. Recent advances in reperfusion therapies have had little impact on the mortality of cardiogenic shock. This may be attributable to the underutilization of life support technology that may assist or completely supplant the patient's own cardiac output until adequate myocardial recovery is established or long-term therapy can be initiated. Clinicians working in the intensive care environment are increasingly likely to be exposed to these technologies. The purpose of this review is to outline the various techniques of mechanical circulatory support and discuss the latest evidence for their use in cardiogenic shock complicating acute myocardial infarction.

Electromagnetic device-device interaction between a new generation implantable pacemaker and left ventricular assist device: recognition and potential solutions

An electromagnetic interaction between St. Jude Medical Inc. (St. Paul, MN, USA) permanent pacemakers and HeartMate II left ventricular assist devices (LVADs) (Thoratec Inc., Pleasanton, CA, USA) has been reported before, but the problem was thought to be resolved in the St. Jude Medical's most recently released pacemaker platform. We report a case of interference between the HeartMate II LVAD and the most recently released St. Jude Medical pacemaker (model no. PM3210; Anthem) and review new developments to overcome the electromagnetic interference problem in this setting.

Early adverse events as predictors of 1-year mortality during mechanical circulatory support

BACKGROUND

Ventricular assist devices (VADs) provide effective treatment for end-stage heart failure; however, most patients experience > or =1 major adverse events (AEs) while on VAD support. Although early, non-fatal AEs may increase the risk of later death during VAD support, this relationship has not been established. Therefore, we sought to determine the impact on 1-year mortality of AEs occurring during the first 60 days of VAD support.

METHODS

A retrospective analysis was performed using prospectively collected data from a single-site database for patients aged > or =18 years receiving left ventricular or biventricular support during 1996 to 2008 and who survived >60 days on VAD support. Fourteen major classes of AEs occurring during this 60-day period were examined. One-year survival rates of patients with and without each major AE were compared.

RESULTS

The study included 163 patients (80% men; mean age, 49.5 years), of whom 87% were European American, 72% had left ventricular support, and 83% were bridge to transplant. The occurrence of renal failure, respiratory failure, bleeding events, and reoperations during the first 60 days after implantation significantly increased the risk of 1-year mortality. After controlling for gender, age, VAD type, and intention to treat, renal failure was the only major AE significantly associated with later mortality (hazard ratio, 2.96; p = .023).

CONCLUSIONS

Specific AEs, including renal failure, respiratory and bleeding events, and reoperations, significantly decrease longer-term survival. Renal failure conferred a 3-fold increased risk of 1-year mortality. Peri-operative management should focus on strategies to mitigate risk for renal failure in order to maximize later outcomes.

Continuous flow left ventricular assist device improves functional capacity and quality of life of advanced heart failure patients

OBJECTIVES

This study sought to assess the impact of continuous flow left ventricular assist devices (LVADs) on functional capacity and heart failure-related quality of life.

BACKGROUND

Newer continuous-flow LVAD are smaller and quieter than pulsatile-flow LVADs.

METHODS

Data from advanced heart failure patients enrolled in the HeartMate II LVAD (Thoratec Corporation, Pleasanton, California) bridge to transplantation (BTT) (n = 281) and destination therapy (DT) (n = 374) trials were analyzed. Functional status (New York Heart Association [NYHA] functional class, 6-min walk distance, patient activity scores), and quality of life (Minnesota Living With Heart Failure [MLWHF] and Kansas City Cardiomyopathy Questionnaires [KCCQ]) were collected before and after LVAD implantation.

RESULTS

Compared with baseline, LVAD patients demonstrated early and sustained improvements in functional status and quality of life. Most patients had NYHA functional class IV symptoms at baseline. Following implant, 82% (BTT) and 80% (DT) of patients at 6 months and 79% (DT) at 24 months improved to NYHA functional class I or II. Mean 6-min walk distance in DT patients was 204 m in patients able to ambulate at baseline, which improved to 350 and 360 m at 6 and 24 months. There were also significant and sustained improvements from baseline in both BTT and DT patients in median MLWHF scores (by 40 and 42 U in DT patients, or 52% and 55%, at 6 and 24 months, respectively), and KCCQ overall summary scores (by 39 and 41 U, or 170% and 178%).

CONCLUSIONS

Use of a continuous flow LVAD in advanced heart failure patients results in clinically relevant improvements in functional capacity and heart failure-related quality of life.

Mechanical circulatory support in the ICCU

The mortality of acute heart failure (AHF) remains high despite advances in treatment. Mechanical circulatory support (MCS) can be applied in AHF, refractory to conventional measures, to improve outcomes. This article aims to describe the current and the prospective role of MCS in the treatment of AHF. The support strategies and the indications of MCS are continuously evolving, including situations considered as contraindications in the past. Appropriate patient selection, advanced device technology and improved patient management have contributed to the substantially improved results. Evolution in device technology results in evolution of the clinical applications of MCS. Earlier application of MCS, with novel, flexible and individualized support strategies is now feasible. Bridging to recovery is the most intriguing support strategy and bridging to future treatments is feasible with long-term support. The progressively expanding role of MCS in the treatment of heart failure is not reflected in the existing guidelines. Being reserved for refractory heart failure, MCS has been applied to the sickest patients who were less amenable to randomization. This explains the lack of robust evidence, but also highlights the value of the progressively improving results. The anticipated wider application of MCS should be better defined, systematically recorded, and guided.

The future is here: ventricular assist devices for the failing heart

Mechanical circulatory support is an important adjunct to the management of patients with advanced heart failure. Technological advances in this area have improved overall survival and decreased the incidence of complications. In addition, they have expanded the population suitable for this therapy. The challenge for clinicians is to translate the clinical evidence into the selection of the most appropriate device that will benefit an individual patient. This paper will review ventricular assist devices currently available and their clinical indications.

Advanced heart failure treated with continuous-flow left ventricular assist device

BACKGROUND

Patients with advanced heart failure have improved survival rates and quality of life when treated with implanted pulsatile-flow left ventricular assist devices as compared with medical therapy. New continuous-flow devices are smaller and may be more durable than the pulsatile-flow devices.

METHODS

In this randomized trial, we enrolled patients with advanced heart failure who were ineligible for transplantation, in a 2:1 ratio, to undergo implantation of a continuous-flow device (134 patients) or the currently approved pulsatile-flow device (66 patients). The primary composite end point was, at 2 years, survival free from disabling stroke and reoperation to repair or replace the device. Secondary end points included survival, frequency of adverse events, the quality of life, and functional capacity.

RESULTS

Preoperative characteristics were similar in the two treatment groups, with a median age of 64 years (range, 26 to 81), a mean left ventricular ejection fraction of 17%, and nearly 80% of patients receiving intravenous inotropic agents. The primary composite end point was achieved in more patients with continuous-flow devices than with pulsatile-flow devices (62 of 134 [46%] vs. 7 of 66 [11%]; P<0.001; hazard ratio, 0.38; 95% confidence interval, 0.27 to 0.54; P<0.001), and patients with continuous-flow devices had superior actuarial survival rates at 2 years (58% vs. 24%, P=0.008). Adverse events and device replacements were less frequent in patients with the continuous-flow device. The quality of life and functional capacity improved significantly in both groups.

CONCLUSIONS

Treatment with a continuous-flow left ventricular assist device in patients with advanced heart failure significantly improved the probability of survival free from stroke and device failure at 2 years as compared with a pulsatile device. Both devices significantly improved the quality of life and functional capacity. (ClinicalTrials.gov number, NCT00121485.)

Quality of life and functional status in patients surviving 12 months after left ventricular assist device implantation

BACKGROUND

As left ventricular assist device (LVAD) support duration increases, quality of life (QoL) becomes a concern. We reviewed the QoL in patients on LVAD support for >or=1 year.

METHODS

We retrospectively reviewed our prospective database for patients supported >or=1 year by HeartMate pulsatile- (HM1) or continuous-flow (HM2) LVADs from 2000 to 2009. Transplant or death before 1 year merited exclusion. Metabolic equivalents of tasks (METs), the Minnesota Living with Heart Failure Questionnaire (MLHFQ), the 6-minute walk distance (6MWD), and New York Heart Association (NYHA) class were reviewed. Complications and re-admissions were assessed.

RESULTS

Thirty patients were supported for >or=1 year (7 HM1s, 23 HM2s). Mean support duration was 594 +/- 173 days. Mean QoL metrics/functional status indicators at 12 months were: 6MWD, 393 +/- 290 m; MET tolerance, 3.3 +/- 1; MLHFQ, 35 +/- 31; and NYHA, 1.4 +/- 0.6. Mean re-admissions/year was 2.9 +/- 2, with a duration of 13.8 +/- 21 days. Three patients were never re-admitted. Mean out-of-hospital time was 471 +/- 172 days (87.3% of days). Infectious complications led to 43% of re-admissions and occurred in the: drive-line (47%) at 442 +/- 236 days; blood (37%) at 472 +/- 257 days; and LVAD pocket (20%) at 550 +/- 202 days. Twenty-three patients (77%) required additional operations (1.7 +/- 1.8/year). The most common indication was drive-line infection, but ranged from ischemic bowel to defibrillator exchange. Eight required LVAD exchanges for mechanical (n = 4), electrical (n = 3), and thrombotic (n = 1) issues.

CONCLUSIONS

Although LVAD support is not without complications, patients spend the majority of time outside the hospital enjoying a good quality of life.

[Assisted circulation: an overview from a clinical perspective]

A higher grade cardiac failure is associated with poor prognosis. In addition to medical conservative treatment and traditional cardiac surgery, in the past years different forms of an assisted circulation evolved. Short-term devices serve to bridge an acute life-threatening situation. The chosen system is dependent on the anticipated clinical course. It is possible to fall back on slightly assisting techniques up to a complete takeover of the cardiac pump function. In the case of severe cardiac failure, the question for transplantation has to be addressed because transplantation is the treatment of choice to date. For an assisted circulation in cases of chronic congestive failure, devices of different generations are available. First generation pulsatile systems are used for assistance of the left ventricle and results have been shown to be superior to medical therapy (REMATCH). With second generation continuous-flow systems, results regarding infections, thromboembolism and also quality of life appear to be further improved. Contact-free centrifugal pumps as third generation systems are in clinical evaluation. So-called "total artificial hearts" are successfully used for bridge-to-transplantation. Taken together, a graded safe treatment of cardiac failure is available today. In the near future, it could be possible to reach results similar to those of cardiac transplantation.

Incidence and patterns of adverse event onset during the first 60 days after ventricular assist device implantation

BACKGROUND

Although ventricular assist devices (VADs) provide effective treatment for end-stage heart failure, VAD support remains associated with significant risk for adverse events (AEs). To date there has been no detailed assessment of the incidence of a full range of AEs using standardized event definitions. We sought to characterize the frequency and timing of AE onset during the first 60 days of VAD support, a period during which clinical observation suggests the risk of incident AEs is high.

METHODS

A retrospective analysis was performed utilizing prospectively collected data from a single-site clinical database including 195 patients aged 18 or greater receiving VADs between 1996 and 2006. Adverse events were coded using standardized criteria. Cumulative incidence rates were determined, controlling for competing risks (death, transplantation, recovery-wean).

RESULTS

During the first 60 days after implantation, the most common AEs were bleeding, infection, and arrhythmias (cumulative incidence rates, 36% to 48%), followed by tamponade, respiratory events, reoperations, and neurologic events (24% to 31%). Other events (eg, hemolysis, renal, hepatic events) were less common (rates <15%). Some events (eg, bleeding, arrhythmias) showed steep onset rates early after implantation. Others (eg, infections, neurologic events) had gradual onsets during the 60-day period. Incidence of most events did not vary by implant era (1996 to 2000 vs 2001 to 2006) or by left ventricular versus biventricular support.

CONCLUSIONS

Understanding differential temporal patterns of AE onset will allow preventive strategies to be targeted to the time periods when specific AE risks are greatest. The AE incidence rates provide benchmarks against which future studies of VAD-related risks may be compared.

Molecular risk stratification in advanced heart failure patients

Risk stratification in advanced heart failure (HF) is crucial for the individualization of therapeutic strategy, in particular for heart transplantation and ventricular assist device implantation. We tested the hypothesis that cardiac gene expression profiling can distinguish between HF patients with different disease severity. We obtained tissue samples from both left (LV) and right (RV) ventricle of explanted hearts of 44 patients undergoing cardiac transplantation or ventricular assist device placement. Gene expression profiles were obtained using an in-house microarray containing 4217 muscular organ-relevant genes. Based on their clinical status, patients were classified into three HF-severity groups: deteriorating (n= 12), intermediate (n= 19) and stable (n= 13). Two-class statistical analysis of gene expression profiles of deteriorating and stable patients identified a 170-gene and a 129-gene predictor for LV and RV samples, respectively. The LV molecular predictor identified patients with stable and deteriorating status with a sensitivity of 88% and 92%, and a specificity of 100% and 96%, respectively. The RV molecular predictor identified patients with stable and deteriorating status with a sensitivity of 100% and 96%, and a specificity of 100% and 100%, respectively. The molecular prediction was reproducible across biological replicates in LV and RV samples. Gene expression profiling has the potential to reproducibly detect HF patients with highest HF severity with high sensitivity and specificity. In addition, not only LV but also RV samples could be used for molecular risk stratification with similar predictive power.